A conventional power conversion apparatus includes: a high-power-factor converter section which performs high-power-factor control for a commercial AC power supply and performs AC/DC conversion; and a DC/DC converter section, provided at the subsequent stage of the high-power-factor converter section, in which the primary side and the secondary side are insulated by a transformer, whereby those sections respectively charge a main battery and a subsidiary battery insulated from each other. When the main battery is preferentially charged, the duty ratio of a switching circuit on the primary side of the transformer is controlled to be constant, and the duty ratio of a switching circuit on the secondary side of the transformer is controlled to be variable. When the subsidiary battery is preferentially charged, the duty ratios of the switching circuits on the primary side and the secondary side of the transformer are controlled to be variable (for example, see Patent Document 1).